Myopia induced by flickering light in guinea pigs: a detailed assessment on susceptibility of different frequencies

AIM: To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies. METHODS: Seventy 2 -week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n =12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured. RESULTS: A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5 ±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89 ±0.3mm, 0.69 ±0.2mm, 1.12 ±0.2mm respectively and with increase in dry weight of sclera by 0.44mg. CONCLUSION: Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could bedisrupted differently by frequency alteration.

Dynamic changes of ocular biometric parameters:a modified form-deprivation myopia model of young guinea pigs

AIM: To evaluate the dynamic ocular biometric changes of a modified form-deprivation myopia model in young guinea pigs. METHODS: The animals were randomly assigned to two groups: the monocularly deprived facemask group (MDF, with all the right eyes covered, n=24) and the normal control group(free of facemask, n=24). Each group was then equally divided into four subgroups which were followed up for 2, 4, 6 and 8 weeks, respectively. Parameters measured from every eye included refraction, corneal curvature, axial length and the dry weight of sclera at the posterior pole. RESULTS: All the facemasks remained in place during the follow-up. The covered eyes developed myopia with the vitreous chamber lengthening and the dry weight of posterior sclera reduced at each time point compared with the contralateral uncovered (P<0.05 at all time points). The changes had a linear correlation with the deprivation time (P<0.05). There were no significant differences in all the parameters between the uncovered eyes of MDF group and the normal control group (P>0.05 at all time points). CONCLUSION: Monocular form deprivation with the facemask is highly effective and non-invasive in inducing axial myopia in guinea pigs. The axial myopia is mainly caused by the increased vitreous chamber length and the weakened posterior sclera rigidity. The form-deprivation eye didn't interfere with the natural development of the contralateral eye.

Electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure

Objective: To investigate the electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure.Methods: Guinea pigs model of iron deficiency anemia complicated with chronic heart failure in 10 guinea pigs of the experimental group was made by feeding a low iron diet,pure water and subcutaneous injection of isoproterenol. The control group consisting of 11 guinea pigs was given normal food, normal water and injected with normal saline. The left ventricular outflow tract model specimen was also prepared. The standard microelectrode technique was used to observe electrophysiological changes of autonomic cells in the outflow tract of left ventricular heart failure complicated with iron deficiency anemia in guinea pig model. The indicators of observation were maximal diastolic potential, action potential amplitude, 0 phase maximal depolarization velocity, 4 phase automatic depolarization velocity, repolarization 50% and 90%, and spontaneous discharge frequency.Results: Compared with the control group, 4 phase automatic depolarization velocity,spontaneous discharge frequency and 0 phase maximal depolarization velocity decreased significantly(P < 0.01) and action potential amplitude reduced(P < 0.01) in model group. Moreover, repolarization 50% and 90% increased(P < 0.01).Conclusions: There are electrophysiological abnormalities of the left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with heart failure.

Effect of green flickering light on myopia development and expression of M1 muscarinic acetylcholine receptor in guinea pigs

AIM： To investigate the effects of green flickering light on refractive development and expression of muscarinic acetylcholine receptor（mAChR） M1 in the eyes of guinea pigs.METHODS： Thirty guinea pigs（15-20 days old） were randomly divided into three groups（n=10/group）. Animals in group I were raised in a completely closed carton with green flickering light illumination. Those in group II were kept in the open top closed carton under normal natural light. Guinea pigs were raised in a sight-widen cage under normal natural light in group III. The refractive status and axial length were measured before and after 8 weeks＇ illumination. Moreover, total RNA extracted from retinal, choroidal, and scleral tissues were determined by real-time reverse transcription polymerase chain reaction（RT-PCR）. The expressions of the receptor M1 were also explored in the retina, choroid, and sclera using immunohistochemistry.RESULTS： There was a remarkable reduction in refractive error and increase in axial length after 8-weeks＇ green flickering light stimulation（P〈0.001）. The expression of M1 receptor mRNA in sclera and retina in myopia group were remarkably lower than that in group II and III（P〈0.01）. Significant reduced expression of M1 receptor stimulated by green flickering light in retina and sclera tissues were also observed（P〈0.05）. However, there was no M1 receptor expression in choroid in 3 groups.CONCLUSION： Myopia can be induced by 8 weeks＇ green flickering light exposure in the animal model. M1 receptor may be involved causally or protectively in myopia development.

An end-to-end anastomosis model of guinea pig bile duct:A 6-mo observation

AIM:To establish the end-to-end anastomosis (EEA) model of guinea pig bile duct and evaluate the healing process of bile duct.METHODS:Thirty-two male guinea pigs were randomly divided into control group,2-,3-,and 6-mo groups after establishment of EEA model.Histological,immunohistochemical and serologic tests as well as measurement of bile contents were performed.The bile duct diameter and the diameter ratio (DR) were measured to assess the formation of relative stricture.RESULTS:Acute and chronic inflammatory reactions occurred throughout the healing process of bile duct.Serology test and bile content measurement showed no formation of persistent stricture in 6-mo group.The DR revealed a transient formation of relative stricture in 2-mo group in comparation to control group (2.94 ± 0.17 vs 1.89 ± 0.27,P=0.004).However,this relative stricture was released in 6-mo group (2.14 ± 0.18,P=0.440).CONCLUSION:A simple and reliable EEA model of guinea pig bile duct can be established with a good reproducibility and a satisfactory survival rate.

Guinea pig model of tuberculosis

Animal models are being developed for testing different vaccine candidates as well as testing of new antitubercular since a long time.Mice,guinea pigs and rabbits are animals which are frequently used.Though each model has got its merits as well as demerits and each of them differ from human tuberculosis in one aspect or the other but none of the model completely mimics the human disease.Out of the different animal species, guinea pig model is one of the better models as it is very sensitive to M.tuberculosis infection but it has certain limitations like paucity of immunological reagents.However,it is the best model for tuberculosis research.

Development and characterization of a guinea pig model for Marburg virus

The Angolan strain of Marburg virus （MARV/Ang） can cause lethal disease in humans with a case fatality rate of up to 90%, but infection of immunocompetent rodents do not result in any observable symptoms. Our previous work includes the development and characterization of a MARV/Ang variant that can cause lethal disease in mice （MARV/Ang-MA）, with the aim of using this tool to screen for promising prophylactic and therapeutic candidates. An intermediate animal model is needed to confirm any findings from mice studies before testing in the gold-standard non-human primate （NHP） model. In this study, we serially passaged the clinical isolate of MARV/Ang in the livers and spleens of guinea pigs until a variant emerged that causes 100% lethality in guinea pigs （MARV/Ang- GA）. Animals infected with MARV/Ang-GA showed signs of filovirus infection including lymphocytopenia, thrombocytopenia, and high viremia leading to spread to major organs, including the liver, spleen, lungs, and kidneys. The MARV/Ang-GA guinea pigs died between 7-9 days after infection, and the LD50 was calculated to be 1.1x10-1 TCID50 （median tissue culture infective dose）. Mutations in MARV/Ang-GA were identified and compared to sequences of known rodent-adapted MARV/Ang variants, which may benefit future studies characterizing important host adaptation sites in the MARV/Ang viral genome.

Electrophysiological changes of Papillary Muscles in Guinea Pigs with iron deficiency anemia and heart failure

Objective:To investigate the changes of left ventricular papillary muscle action potentials in guinea pigs with iron deficiency anemia and heart failure.Methods:A total of 20 cases of iron deficiency anemia with heart failure were treated with experimental group and 10 normal guinea pigs as control group. Blood samples were collected to determine hemoglobin content, red blood cell number and whole blood iron index, and the changes of cardiac function and hemodynamics were detected by 6240 biological signal collection system to determine whether the model was successful or not, Intracellular microelectrode technique was used to determine the action potentials of the papillary muscles in the model group and the control group. the potential amplitudes (APA), overshoot values (APA), maximum depolarization rate (Vmax), 20 % of repolarization, 50 % and 90 % of repolarization (APD20, APD50 and APD90 ) and the average velocity of repolarization were measured. Compare statistical difference between the model group and the control group.Results: 14 cases of model group survived completely, compared with control group, APD50 and APD90 prolonged, and the average velocity decreased.Conclusions: the action potential repolarization duration in the guinea pig papillary muscle of iron deficiency anemia with heart failure is prolonged, and the average repolarization velocity is slow.

Guinea pigs as an animal model for sciatic nerve injury

The overwhelming use of rat models in nerve regeneration studies is likely to induce skewness in treatment outcomes.To address the problem,this study was conducted in 8 adult guinea pigs of either sex to investigate the suitability of guinea pig as an alternative model for nerve regeneration studies.A crush injury was inflicted to the sciatic nerve of the left limb,which led to significant decrease in the pain perception and neurorecovery up to the 4th weak.Lengthening of foot print and shortening of toe spread were observed in the paw after nerve injury.A 3.49 ± 0.35 fold increase in expression of neuropilin 1（NRP1） gene and 2.09 ± 0.51 fold increase in neuropilin 2（NRP2） gene were recorded 1 week after nerve injury as compared to the normal nerve.Ratios of gastrocnemius muscle weight and volume of the experimental limb to control limb showed more than 50% decrease on the 30 th day.Histopathologically,vacuolated appearance of the nerve was observed with presence of degenerated myelin debris in digestion chambers.Gastrocnemius muscle also showed degenerative changes.Scanning electron microscopy revealed loose and rough arrangement of connective tissue fibrils and presence of large spherical globules in crushed sciatic nerve.The findings suggest that guinea pigs could be used as an alternative animal model for nerve regeneration studies and might be preferred over rats due to their cooperative nature while recording different parameters.

Efficacy Assessment of Whitening Cosmetics in Animal Models

Animal skin is generally preferred to evaluate the efficacy and safety:several animal models have been used,e.g.,the guinea pig,the mouse,and the zebrafish.The epidermis of guinea pigs displays a moderate number of melanocytes and melanosomes distributed in a similar way to human skin.Guinea pig and human skins have given the close morphologic and functional similarities(similar epidermis thickness,similar epidermal cells turnover time,etc.).The zebrafish presents several advantages,including easy maintenance and handling of the animals,short generation times,and high efficiency of drug penetration through the skin.To establish the animal model and to assess whitening efficacy and safety for whitening products.

两种呼吸道感染途径建立豚鼠结核模型的比较

目的建立不同剂量的滴鼻和气管内定量气溶胶感染途径的豚鼠结核模型,并进行对比分析,为标准化豚鼠呼吸道感染结核模型建立提供基础。方法雌性哈氏豚鼠24只,随机分为6组,每组4只,气管内定量气溶胶和滴鼻途径感染豚鼠均用两个剂量,均分为3个组(A、B、C组,D、E、F组)。气溶胶感染途径分为3组:A组(气溶胶对照组,未感染对照)、B组(气溶胶低剂量感染组,5×10^(2)CFU)和C组(气溶胶高剂量感染组,5×10~3 CFU);滴鼻感染途径也分为3组:D组(滴鼻对照组,未感染对照)、E组(滴鼻低剂量感染组,1×10^(4)CFU)和F组(滴鼻高剂量感染组,5×10^(4)CFU)。结核菌(Mycobacterium tuberculosis,Mtb)感染豚鼠后观察其一般表现,第14天解剖,取肺、脾、肝组织,记录大体病变,用苏木素-伊红(HE)染色分析组织中结核肉芽肿病变,采用抗酸染色分析原位菌的分布和数量,菌分离培养分析脏器荷菌量。结果4个感染组(B、C、E、F组)豚鼠的肺、脾、肝均有肉眼可见的结核病灶及HE染色后可见结核肉芽肿病变。抗酸染色和荷菌量提示,B、C组的菌主要分布在肺组织,少数分布在脾和肝,荷菌量为104~10^(5)CFU/mL;E、F组的菌在肺、脾、肝均有分布,荷菌量为104~10^(5)CFU/mL。B、C、E、F组的病变和荷菌量,组间均无显著性差异,但B、C、F组内病理学及病原学指标的标准差较小。结论两个剂量的气溶胶和滴鼻途径均能制备豚鼠急性结核模型,病理学检查和病原学分析表明,气溶胶5×10^(2)CFU Mtb即可成功制备该模型,且模型均一性较好;滴鼻途径5×10^(4)CFU Mtb也可制备更均一的豚鼠急性结核模型,然而气溶胶5×10^(2)CFU比滴鼻途径5×10^(4)CFU发展为更严重的急性结核模型。

变应性鼻炎相关动物模型研究进展

目的综述变应性鼻炎(allergic rhinitis,AR)相关动物模型的研究进展,为深入研究AR的发病机制及药物评价提供参考。方法通过对国内外文献的查阅,从AR模型动物的种类、特点、模型种类、建模方法、模型成功的标准和评价指标等方面进行总结。结果变应性鼻炎相关动物模型包括西医病理模型和中医病症结合模型,动物选择多使用豚鼠、小鼠、大鼠、新西兰兔等。结论总结已有AR动物模型的种类、方法和评价指标以及在AR发病机制研究中的应用,可为后续AR的深入研究提供参考。

豚鼠耳内镜解剖及手术训练模型的建立

目的探讨以活体豚鼠构建耳内镜解剖及手术操作训练动物模型的可行性。方法以8只健康成年豚鼠为实验动物,通过开放上鼓室并磨除外耳道上壁建立满足耳内镜进行观测和操作的空间,构建耳内镜操作的模型。由同一名住院医师分别在8只豚鼠完成耳内镜下颞骨的解剖开放及基本手术步骤,评估内镜下手术操作的难度及完成情况;并测量乳突开放后的前后径、上下径,上鼓室外侧壁以及外耳道上壁开放后的前后径、上下径,以及耳内镜的最大进镜深度。结果内镜下清晰展现豚鼠鼓室内精细结构,除了鼓索神经的游离保留、去除外侧听骨后暴露镫骨这两个步骤有所难度以外,其余步骤如鼓膜与锤骨的分离、暴露锤砧复合体、去除蜗壳观察蜗轴、内镜下面神经鼓室段暴露等操作均可轻松完成。开放后的乳突前后径和上下径分别为3.56±0.21、3.89±0.16 mm,开放后的上鼓室和外耳道上壁前后径和上下径分别为5.60±0.09 mm、6.02±0.10 mm,耳内镜最大进镜深度为15.14±0.24 mm。结论豚鼠作为耳内镜操作训练动物模型,能够提供较为真实的手术操作体验,有助于初学者进行耳内镜手术基本操作技巧和耳内镜解剖训练。

实验性近视豚鼠模型研究进展

近视发病率逐年上升,严重影响着公众生活质量,为探索近视的发病机制,迄今已经建立了多种实验性近视动物模型。豚鼠在近视研究方面具有明显的优点,目前是亚洲实验室最常见的近视动物模型,但是不同的造模方式各有优缺点,了解不同的造模方式有利于选择适合的动物模型以及匹配不同的研究目的,可使研究结果更具说服力。本文对近年来豚鼠近视模型的不同造模方式及其特点、以及豚鼠眼部组织形态学的变化等方面进行简要综述,为进一步研究近视发生发展的分子机制寻找新的治疗策略提供一定的参考。

基于多指标评价的胆囊炎豚鼠模型的建立与优化

目的探讨胆囊炎豚鼠模型的建立及优化方法,为进一步优化实验设计和研究胆囊炎的发病、治疗及作用机制提供实验基础。方法采取盐酸林可霉素皮下注射的方式,建立胆囊炎豚鼠模型,通过观察豚鼠一般状态、胆囊B超、血常规指标和肝胆组织病理学改变,确定胆囊炎模型的稳定性及应用前景。结果一般状态观察发现,模型组豚鼠出现不同程度的饮食减少、体质量下降、活动减少、毛发疏松无光泽、精神萎靡或烦躁不安等。胆囊B超结果显示,与对照组豚鼠比较,造模剂量越高,豚鼠的胆囊壁增厚越明显(P<0.05);血常规指标检测发现,造模剂量越高,血液炎性指标白细胞计数(white blood cell count,WBC)、淋巴细胞计数(lymphocyte,LYM)、中性粒细胞计数(neutrophil,NEUT)、单核细胞计数(monocyte,MONO)上升越显著(P<0.05);苏木精-伊红染色结果显示,造模剂量越高,胆囊和肝脏组织结构病变、炎性细胞浸润、肝细胞变性坏死等病理变化更加明显。结论本研究通过影像学指标结合血液及病理指标,多因素综合评价胆囊炎造模效果以及炎症模型的稳定性,较常规的胆囊病理分析法或结合血清炎性细胞因子酶联免疫吸附试验检测法更为直观、精确且廉价,且为药物治疗效果评价提供科学有效的检测指标;同时,确定豚鼠胆囊炎造模剂量为盐酸林可霉素120mg/kg的模型最为稳定,且不易自愈。

应用Python编程数字化测量豚鼠角膜曲率及离心率

目的探索一种编程数字化技术和数学几何原理相结合对豚鼠眼球形态学参数进行量化分析的方法。方法选取22只3周龄清洁级雄性三色豚鼠,采用过量麻醉法处死并取出眼球,采用1300万像素微距仪的高拍模式进行水平面及矢状面拍照,图片导入pycharm编程软件。应用Python 3.9预先编写好的分析程序,先通过刻度尺获取图片像素与实际距离的换算系数,再对角膜表面进行圆弧拟合及圆锥曲线拟合。圆弧拟合后的结果经换算后计算出豚鼠的角膜曲率半径;通过圆锥曲线通用方程拟合(Ax^(2)+Bxy+Cy^(2)+Dx+Ey+F=0),得出角膜表面的离心率e值;通过对全角膜及中央区3 mm的拟合,评估角膜的非球面性质。结果应用Python编程数字化方法可以完整清晰地展现豚鼠的角膜轮廓。横切面上,数字化拟合中央3 mm、数字化拟合全角膜以及曲率计测量全角膜曲率比较,差异无统计学意义(F=1.693,P=0.190);矢状面上,3种方法测得的角膜曲率比较,差异有统计学意义(F=3.500,P=0.030),其中曲率计测量全角膜的角膜曲率明显大于数字化拟合全角膜,差异有统计学意义(P<0.05)。横切面和矢状面上,3种方法测得的角膜曲率半径比较,差异均无统计学意义(F=1.817,P=0.170;F=2.050,P=0.133)。离心率测量结果显示,横切面和矢状面数字化拟合中央区3 mm处e值分别为0.55±0.15和0.53±0.17,分别低于数字化拟合全角膜e值的0.66±0.10和0.64±0.14,差异均有统计学意义(t=-4.860、-5.210,均P<0.01)。结论应用Python编程数字化方法测量豚鼠角膜曲率及离心率切实可行。

豚鼠与人眼球结构及生物学参数的比较研究进展

豚鼠是目前国内最为广泛使用的研究视觉系统的动物模型之一,尽管其眼球的解剖和形态特征以及生理功能方面都与人类接近,但两者间的差异性也是我们不可忽视的。充分了解豚鼠和人眼之间存在的解剖、生理和病理学差异,能够为眼科研究者合理、有效地选择及建立相关疾病动物模型提供科学的理论依据。因此,本文就眼球的主要结构及其生物学参数对人与豚鼠的眼球进行比较分析,为以豚鼠为动物模型的视觉系统科学研究提供一定的参考价值。

盐酸灌注豚鼠食管反流性疾病模型的建立

目的:利用反复酸灌注的方法模拟人胃食管反流,建立豚鼠食管炎模型,以便为探讨反流相关性呼吸系统疾病提供实验动物模型。方法:将胃管插入豚鼠食管至食管中、下端,灌注含0.5%胃蛋白酶的0.1mol/LHCl(8drops/min,20min/d),连续灌注14d。结果:酸灌注后出现明显食管炎症病理改变,光镜下可见食管下段粘膜基底细胞层增生,乳头延长、角化过度。部分食管鳞状上皮过度增生、核增大、变圆。固有层慢性炎症细胞浸润明显,粘膜下层内血管扩张、充血。气管、支气管粘膜也见水肿、基底膜增厚,部分上皮脱落,粘膜和粘膜下层炎症细胞浸润。结论:连续酸灌注的方法成功地复制了豚鼠反流性食管炎模型,同时伴有气管、支气管粘膜炎症,为探讨反流相关性呼吸系统疾病的发病机制提供了帮助。

强的松豚鼠肾虚模型的听力观察

为了解肾虚与听力的关系，利用糖皮质激素模拟“肾虚”动物模型，应用耳廓反射（ＰＲ）阈及听性脑干反应（ＡＢＲ）监测“肾虚”模型豚鼠的听力变化，初步发现：“肾阴虚”及“肾阳虚”实验豚鼠均出现了听力下降现象，但“肾阴虚”的听力下降以６ｋＨｚ为明显，而“肾阳虚”的听力下降以２ｋＨｚ为明显，且“肾阳虚”时２～８ｋＨｚ听力下降的程度均比“肾阴虚”严重，动物听力下降的程度与其全身“虚弱”症状的程度一致。以上结果为探讨“肾开窍于耳”的实质提供了新的实验资料。

壁虎粉对哮喘豚鼠模型干预作用的实验研究

目的探讨壁虎粉平喘的部分作用机理。方法采用卵蛋白致敏激发豚鼠哮喘为模型,观察壁虎粉干预组、氨茶碱对照组和哮喘模型组动物哮喘发病情况,肺泡灌洗液(BALF)中EOS含量及豚鼠肺组织病理学的改变。结果壁虎粉和氨茶碱组BALF中EOS含量明显低于哮喘模型组,病理学提示壁虎粉能抑制局部炎症细胞浸润、保护气管粘膜的完整性。结论壁虎粉可通过抑制气道炎症,促进EOS凋亡等途径发挥平喘作用。